CA Fin Code Section 6156

(a)

Any vacancy among directors, not filled by the members or stockholders, may be filled by a majority vote of the remaining directors, though less than a quorum, by electing a director to serve until the next annual meeting of the members or stockholders, at which time a director shall be elected to fill the vacancy for the unexpired term for the class of director in which the vacancy exists.

(b)

In the event of a vacancy on the board of directors from any cause, the remaining directors shall have full power and authority to continue direction of the association until the vacancy is filled.